Lipids 1-3

Question 1

Lipids

Answer 1

Insoluble in water

Question 2

Functions of lipids

Answer 2

Signalling molecules
Fat soluble vitamins eg A D E K
Activity of enzymes
Structural element of membranes

Question 3

Classes of lipids

Answer 3

TAG, fatty acids, phospholipids, glycolipid and steroids

Question 4

Fatty acid

Answer 4

Hydrophobic carbon and carboxyl

Question 5

In vivo are double bonds usually cis or trans?

Answer 5

Cis

Question 6

What is the terminal from methyl called?

Answer 6

Omega carbon

Question 7

4 types of fatty acid

Answer 7

• good
• essential
• bad
• really bad

Question 8

Good fat

Answer 8

Polyunsaturated fatty acid eg vegetable oil

Question 9

Essential fatty acid

Answer 9

Lineolic and lineolic acid - humans cannot introduce double bonds past carbon 9
Aracidonic acid from lineolic acid needed for echosanoids

Question 10

Bad fat

Answer 10

Saturated fat eg beef

Question 11

Really bad fat

Answer 11

Trans fatty acids - hydrogenation of vegetable oil

Question 12

TAG

Answer 12

3 fatty acid, glycerol

fuel and insulation

Question 13

Phospholipids

Answer 13

fatty acid, phosphate and glycerol

amphipathic

Question 14

What is the main dietary lipid?

Answer 14

TAG

Also fatty acids, cholesterol, cholesterol esters and phospholipids

Question 15

Where is the main site of digestion?

Answer 15

Small intestine

Question 16

What is TAG degraded by?

Answer 16

Pancreatic lipase to monoacylglycerol and 2 fatty acids

Question 17

Cholesterol ester ==>

Answer 17

Cholesterol and fatty acid

Question 18

Phospholipid =>

Answer 18

Fatty acid and lysophospholipid

Question 19

What do the products form?

Answer 19

Mixed micelles by emulsification with bile salts (derived from cholesterol) and peristalsis

Question 20

What happens to the micelle

Answer 20

Approaches brush border of intestine and release products which are resynthesized for export

Question 21

Steatorrhea

Answer 21

Gall bladder removed so no bladder leading to excess fat in faeces - CF

Question 22

Insoluble fatty acids repackaged into?

Answer 22

Chylomicrons for transport in the blood

Question 23

What is TAG in chylomicrons broken down to?

Answer 23

Glycerol and fatty acids

Question 24

What are the fatty acids not used by?

Answer 24

The brain

Question 25

What happens to chylomicron without TAG

Answer 25

Go to the liver

Question 26

What is fat in adipose tissue broken down to and by what?

Answer 26

fatty acids using hormone sensitive lipase

Question 27

What is HSL activated and inactivated by?

Answer 27

``` Activated = phosphorylation in response to epinephrine inactivated = high blood glucose ```

Question 28

How are fatty acids travelled in blood

Answer 28

Complex with albumin | Lipoproteins

Question 29

4 classes of lipoprotein

Answer 29

- Huge chylomicron in liver - VLDL - LDL - HDL

Question 30

Where does beta oxidation occur?

Answer 30

Matrix of mitochondria

Question 31

What does beta oxidation do and what are the products

Answer 31

Degrade fatty acids 2 carbons at a time | Acetyl coA, NADH and FADH2

Question 32

Activation

Answer 32

Fatty acid activated in cytosol to fatty acyl coA

Question 33

Transport

Answer 33

Cartinine shuttle as coA swapped as too big | Malonyl coA inhibits

Question 34

Degradation

Answer 34

- Dehydrogenation FAD=>FADH2 double bond 2ATP - Hydration - dehydrogenation NAD=>NADH 3ATP - thiolysis - acetyl coA 12ATP

Question 35

Where do long chain fatty acids undergo preliminary oxidation?

Answer 35

Peroxisomes

Question 36

Are fatty acids gluconeogenic?

Answer 36

No

Question 37

What does excess acetyl coA produce?

Answer 37

Ketone bodies

Question 38

When are ketone bodies used?

Answer 38

In starvation - cardiac, skeletal muscle and brain | Acetone - sweet smelling breath

Question 39

Where are ketone bodies made?

Answer 39

Liver

Question 40

What are fatty acids made from?

Answer 40

Acetyl coA

Question 41

What are the fates of acetyl coA

Answer 41

- citric acid cycle - steroids and cholesterol - ketone bodies

Question 42

Where does fatty acid synthesis occur?

Answer 42

Liver, lactating mammary glands and adipose tissue | CYTOSOL

Question 43

What does fatty acid synthesis use?

Answer 43

ATP and NADPH

Question 44

Shuttle

Answer 44

Citrate shuttle - acetyl coA in mitochondria so needs shuttled into cytosol Occurs when citrate concentration is high

Question 45

Product of fatty acid synthesis

Answer 45

Palmatic acid

Question 46

Enzymes in fatty acid synthesis

Answer 46

Acetyl coA carboxylase | Fatty acid synthase

Question 47

What is needed for malonyl coA synthesis?

Answer 47

Acetyl coA carboxylase - activated by citrate +insulin and inhibited by palmitoyl coA, Glucagon+epinephrine

Question 48

What is used for cleaving?

Answer 48

Thioesterase

Question 49

Name the steps

Answer 49

``` Elongation Reduction Dehydration Reduction Cleavage ```

Question 50

Carrier protein in synthesis?

Answer 50

ACP

Question 51

Steroid

Answer 51

Chemical substances synthesised by cholesterol

Question 52

Eicosanoids

Answer 52

Derived from unsaturated fatty acids - omega 3/6 | precursor to prostaglandins, leukotrienes and thromboxanes

Question 53

Cholesterol fates

Answer 53

Steroids vitamin D Bile salts in liver

Question 54

Prostaglandins

Answer 54

Uterine contraction | Pain and fever

Question 55

Thromboxanes

Answer 55

Blood clotting

Question 56

Leukotrienes

Answer 56

Prevent asthma by inhibition